Electric power generating systems are known comprising a number of alternators, each driven by at least one internal combustion engine (e.g. a diesel or turbogas engine) and generating an alternating output voltage; and the engines are closed-loop controlled to run at substantially the same speed, so that the output voltages of the alternators have the same frequency and phase.
In such known systems, the outputs of the alternators are arranged parallel to sum the output currents which are used to supply a local electric network powering a number of electric loads.
The above systems can also be used to advantage on ships to power on-board electric user devices (motors, lighting, electronic equipment, etc.).
As stated, the internal combustion engines must operate at the same constant speed to sum the alternating output currents.
This can pose serious drawbacks, in that, in many practical applications, the speed of the internal combustion engine does not correspond to the speed which maximizes efficiency and/or reduces consumption and/or minimizes wear of the engine.
As a result, in known power generating systems, consumption is normally high, efficiency less than optimum at the various power outputs, and wear of mechanical component parts is severe.